Codeigniter pressing logout button and disable the back browser button

Question

Hello guys i am using CodeIgniter Framework, i have a problem within after logout, the session is already destroyed and redirect to login form, and after redirecting to login form, the browser back button can be backed to dashboard but there are errors because of the session was destroyed already. All i want is to disable the back button of the browser or anything that my previous cant be loaded. I have read other posts about this problem and tried their solution but it doesn't work. I have already pasted this code based on what I've read in other post in my constructor.

The code that I've seen from the post and posted in my constructor :
 header("cache-Control: no-store, no-cache, must-revalidate");
        header("cache-Control: post-check=0, pre-check=0", false);
        // HTTP/1.0
        header("Pragma: no-cache");
        // Date in the past
        header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
        // always modified
        header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 

here is my logout:

 $sess_array = array(
        'username' => ''
        );
        $this->session->unset_userdata('logged_in', $sess_array);
        $this->session->sess_destroy();
        redirect('auth', 'refresh');

here is from my dashboard :

    <li>                                 
<a href="<?= base_url('auth/logout') ?>"><i3 class="glyphicon glyphicon-off"></i3> Logout</a>
   </li>

Answer 1

I tired to implement this option but it doesn't works well. So i implement new logic on this.

Simply check is session is set in every main methods. Below code help you

In logout(define in controller)

function __construct()
{
    parent::__construct();
    ob_start(); # add this
}

public function logout()
{
    $this->load->driver('cache');
    $this->session->sess_destroy();
    $this->cache->clean();
    ob_clean();
    redirect('home'); # Login form or some other page         
}

In dashboard(Function)

public function home()
{
    $logged_in = $this->session->userdata('logged_in');
    if($logged_in != TRUE || empty($logged_in))
    {
        #user not logged in
        $this->session->set_flashdata('error', 'Session has Expired');
        redirect('user_logging'); # Login view
    }
    else
    {
        #user Logged in
        $this->load->view("viewname",$data);
    }
}

In Login(function)

$session = array(
    'username'  => $name,
    'logged_in' => TRUE
);

$this->session->set_userdata($session);